mysql - 无法使用 SpringMVC 和 Hibernate Autowiring 字段

Question

我终于找到问题的原因了。它并不像错误注释显示的那么清楚。这是由我的 MyTutorialWebAppInitializer 引起的。

以前是这样的:

public class MyTutorialWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[] { RootConfig.class };
    }

    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] { WebConfig.class };
    }

    protected String[] getServletMappings() {
        return new String[]{"/home/","/about/"};
    }
}

我更改如下，现在一切正常!!!

public class MyTutorialWebAppInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
        appContext.register(WebConfig.class);

        ServletRegistration.Dynamic dispatcher = servletContext.addServlet(
                "SpringDispatcher", new DispatcherServlet(appContext));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/about/","/home/");

    }
}

<小时/>

嗨，我是 JEE Web 开发的新手。我正在使用 Spring MVC 和 Hibernate 连接 MySql 数据库。 Fowlloing 是我第一次访问数据库的一个非常简单的例子，但我被编译错误困扰了很长一段时间。如有任何建议，我们将不胜感激。

错误信息:

>     Caused by: org.springframework.beans.factory.BeanCreationException: Error
> creating bean with name 'puzzleServiceImpl': Injection of autowired
> dependencies failed; nested exception is
> org.springframework.beans.factory.BeanCreationException: Could not
> autowire field: private com.mytutorial.dao.PuzzleDAO
> com.mytutorial.service.impl.PuzzleServiceImpl.puzzleDAO; nested
> exception is org.springframework.beans.factory.BeanCreationException:
> Error creating bean with name 'puzzleDAOImpl': Injection of autowired
> dependencies failed; nested exception is
> org.springframework.beans.factory.BeanCreationException: Could not
> autowire field: private org.hibernate.SessionFactory
> com.mytutorial.dao.impl.PuzzleDAOImpl.sessionFactory; nested exception
> is org.springframework.beans.factory.NoSuchBeanDefinitionException: No
> qualifying bean of type [org.hibernate.SessionFactory] found for
> dependency: expected at least 1 bean which qualifies as autowire
> candidate for this dependency. Dependency annotations:
> {@org.springframework.beans.factory.annotation.Autowired(required=true)}
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:288)
>   at
> org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1122)
>   at
> org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:522)
>   at
> org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
>   at
> org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
>   at
> org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
>   at
> org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
>   at
> org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:910)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:853)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:768)
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:486)
>   ... 60 more Caused by:
> org.springframework.beans.factory.BeanCreationException: Could not
> autowire field: private com.mytutorial.dao.PuzzleDAO
> com.mytutorial.service.impl.PuzzleServiceImpl.puzzleDAO; nested
> exception is org.springframework.beans.factory.BeanCreationException:
> Error creating bean with name 'puzzleDAOImpl': Injection of autowired
> dependencies failed; nested exception is
> org.springframework.beans.factory.BeanCreationException: Could not
> autowire field: private org.hibernate.SessionFactory
> com.mytutorial.dao.impl.PuzzleDAOImpl.sessionFactory; nested exception
> is org.springframework.beans.factory.NoSuchBeanDefinitionException: No
> qualifying bean of type [org.hibernate.SessionFactory] found for
> dependency: expected at least 1 bean which qualifies as autowire
> candidate for this dependency. Dependency annotations:
> {@org.springframework.beans.factory.annotation.Autowired(required=true)}
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:514)
>   at
> org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:285)
>   ... 71 more Caused by:
> org.springframework.beans.factory.BeanCreationException: Error
> creating bean with name 'puzzleDAOImpl': Injection of autowired
> dependencies failed; nested exception is
> org.springframework.beans.factory.BeanCreationException: Could not
> autowire field: private org.hibernate.SessionFactory
> com.mytutorial.dao.impl.PuzzleDAOImpl.sessionFactory; nested exception
> is org.springframework.beans.factory.NoSuchBeanDefinitionException: No
> qualifying bean of type [org.hibernate.SessionFactory] found for
> dependency: expected at least 1 bean which qualifies as autowire
> candidate for this dependency. Dependency annotations:
> {@org.springframework.beans.factory.annotation.Autowired(required=true)}
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:288)
>   at
> org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1122)
>   at
> org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:522)
>   at
> org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
>   at
> org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
>   at
> org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
>   at
> org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
>   at
> org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:910)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:853)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:768)
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:486)
>   ... 73 more Caused by:
> org.springframework.beans.factory.BeanCreationException: Could not
> autowire field: private org.hibernate.SessionFactory
> com.mytutorial.dao.impl.PuzzleDAOImpl.sessionFactory; nested exception
> is org.springframework.beans.factory.NoSuchBeanDefinitionException: No
> qualifying bean of type [org.hibernate.SessionFactory] found for
> dependency: expected at least 1 bean which qualifies as autowire
> candidate for this dependency. Dependency annotations:
> {@org.springframework.beans.factory.annotation.Autowired(required=true)}
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:514)
>   at
> org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:285)
>   ... 84 more Caused by:
> org.springframework.beans.factory.NoSuchBeanDefinitionException: No
> qualifying bean of type [org.hibernate.SessionFactory] found for
> dependency: expected at least 1 bean which qualifies as autowire
> candidate for this dependency. Dependency annotations:
> {@org.springframework.beans.factory.annotation.Autowired(required=true)}
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:986)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:856)
>   at
> org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:768)
>   at
> org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:486)
>   ... 86 more

DataPuzzle.java:

    package com.mytutorial.data;

import javax.persistence.*;

/**
 * Created by bjhl on 11/16/16.
 */

@Entity
@Table(name = "puzzles")
public class DataPuzzle {

    @Id
    @GeneratedValue
    @Column(name = "id")
    private Integer id;

    @Column(name = "title")
    private String title;

    @Column(name = "author")
    private String author;

    @Column(name = "price")
    private float price;

    public Integer getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }

    public String getAuthor() {
        return author;
    }

    public float getPrice() {
        return price;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public void setPrice(float price) {
        this.price = price;
    }
}

PuzzleDAO:

    public interface PuzzleDAO {

    public void addPuzzle(DataPuzzle dataPuzzle);
    public List<DataPuzzle> getPuzzles();
    public void removePuzzle(Integer id);

}

PuzzleDAOImpl

package com.mytutorial.dao.impl;

import com.mytutorial.dao.PuzzleDAO;
import com.mytutorial.data.DataPuzzle;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import java.util.List;

;

/**
 * Created by bjhl on 11/16/16.
 */


@Repository
public class PuzzleDAOImpl implements PuzzleDAO {

    @Autowired
    private SessionFactory sessionFactory;

    public void addPuzzle(DataPuzzle dataPuzzle) {
        sessionFactory.getCurrentSession().save(dataPuzzle);
    }

    public List<DataPuzzle> getPuzzles() {
        return sessionFactory.getCurrentSession().createQuery("from DataPuzzle")
                .list();
    }

    public void removePuzzle(Integer id) {
        DataPuzzle puzzle = (DataPuzzle) sessionFactory.getCurrentSession().load(
                DataPuzzle.class, id);
        if (null != puzzle) {
            sessionFactory.getCurrentSession().delete(puzzle);
        }
    }
}

PuzzleService:

    package com.mytutorial.service;

import com.mytutorial.data.DataPuzzle;

import java.util.List;

/**
 * Created by bjhl on 11/16/16.
 */
public interface PuzzleService {

    public void addPuzzle(DataPuzzle dataPuzzle);
    public List<DataPuzzle> getPuzzles();
    public void removePuzzle(Integer id);
}

PuzzleServiceImpl

    package com.mytutorial.service.impl;

import com.mytutorial.dao.PuzzleDAO;
import com.mytutorial.data.DataPuzzle;
import com.mytutorial.service.PuzzleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

/**
 * Created by bjhl on 11/16/16.
 */

@Service
public class PuzzleServiceImpl implements PuzzleService {

    @Autowired
    private PuzzleDAO puzzleDAO;

    @Transactional
    public void addPuzzle(DataPuzzle dataPuzzle) {
        puzzleDAO.addPuzzle(dataPuzzle);
    }

    @Transactional
    public List<DataPuzzle> getPuzzles() {
        return puzzleDAO.getPuzzles();
    }

    @Transactional
    public void removePuzzle(Integer id) {
        puzzleDAO.removePuzzle(id);
    }
}

WebConfig

package com.mytutorial.config;

import org.apache.commons.dbcp.BasicDataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.orm.hibernate4.HibernateTransactionManager;
import org.springframework.orm.hibernate4.LocalSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

import javax.annotation.Resource;
import javax.sql.DataSource;
import java.util.Properties;

/**
 * Created by bjhl on 11/15/16.
 */

@Configuration
@EnableWebMvc
@EnableTransactionManagement
@ComponentScan("com.mytutorial")
@PropertySource("classpath:jdbc.properties")
public class WebConfig{

    private static final String PROPERTY_NAME_DATABASE_DRIVER = "db.driver";
    private static final String PROPERTY_NAME_DATABASE_PASSWORD = "db.password";
    private static final String PROPERTY_NAME_DATABASE_URL = "db.url";
    private static final String PROPERTY_NAME_DATABASE_USERNAME = "db.username";

    private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
    private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
    private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN = "entitymanager.packages.to.scan";

    @Resource
    private Environment env;

    @Bean
    public DataSource dataSource() {
        BasicDataSource dataSource = new BasicDataSource();

        dataSource.setDriverClassName(env.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));
        dataSource.setUrl(env.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));
        dataSource.setUsername(env.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));
        dataSource.setPassword(env.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));

        return dataSource;
    }

    @Bean
    public LocalSessionFactoryBean sessionFactory() {
        LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource());
        sessionFactoryBean.setPackagesToScan(env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
        sessionFactoryBean.setHibernateProperties(hibProperties());
        return sessionFactoryBean;
    }

    private Properties hibProperties() {
        Properties properties = new Properties();
        properties.put(PROPERTY_NAME_HIBERNATE_DIALECT, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
        properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));
        return properties;
    }

    @Bean
    public HibernateTransactionManager transactionManager() {
        HibernateTransactionManager transactionManager = new HibernateTransactionManager();
        transactionManager.setSessionFactory(sessionFactory().getObject());
        return transactionManager;
    }

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver resolver =
                new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/view/");
        resolver.setSuffix(".html");
        resolver.setExposeContextBeansAsAttributes(true);
        return resolver;
    }


}

如果我从PuzzleDAOImpl中删除@Autowired，编译错误就会消失，但这会导致数据库连接出现其他问题。谁能救救我!

Answer 1

您需要在代码中修复以下内容，

 @Service
 public class PuzzleServiceImpl implements PuzzleService {

应该是

 @Service("puzzleService")
 public class PuzzleServiceImpl implements PuzzleService {

DAO/存储库组件也是如此，

 @Repository
 public class PuzzleDAOImpl implements PuzzleDAO {

应该是

 @Repository("puzzleDAO")
 public class PuzzleDAOImpl implements PuzzleDAO {

编辑:尝试按如下方式限定您的 session 工厂，

     @Bean(name = "sessionFactory")
     public LocalSessionFactoryBean sessionFactory() {
          LocalSessionFactoryBean sessionFactoryBean = new LocalSessionFactoryBean();
          sessionFactoryBean.setDataSource(dataSource());
          sessionFactoryBean.setPackagesToScan(env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
          sessionFactoryBean.setHibernateProperties(hibProperties());
          return sessionFactoryBean;
      }